The present invention relates to a system of observing a process occurring within a sealed or open vessel, and more particularly, the present invention relates to a remote vision system that records images of a process liquid, bubbles or particles in the liquid, and surfaces within the vessel.
The production of biopharmaceuticals, enzymes and other biotechnology derived compounds typically takes place in a vessel, such as a bioreactor, fermenter, or the like. Such vessels may include a sparger for introducing a gas, such as compressed air, directly within the liquid in the form of bubbles. The bubbles must be of an appropriate size and volume and be injected at an appropriate rate into the process liquid so that the gas can be absorbed uniformly throughout the process liquid before reaching the surface of the liquid. Such vessels also typically include an agitator provided as one or more rotating blades.
Problems can arise with respect to the injection of gas into the process liquid. For example, if the size, volume, quantity, or injection rate of bubbles and/or parameters, such as bubble size versus volume, is too great, a significant quantity of the bubbles will reach the surface of the process liquid without being absorbed and will create an undesirable amount of foam in the headspace of the vessel. The presence of too much foam can effectively close off the upper surface of the process liquid, thereby starving the culture of oxygen, and/or can clog filters. Problems can also occur if the size, volume, quantity, or injection rate of bubbles and/or parameters, such as bubble size versus volume, is too small. In this case, only localized areas of the process liquid will be sufficiently aerated and an overall sufficient amount of absorption and uniform absorption will fail to occur.
Problems are also presented by the agitator. The agitator can function to shear the bubbles to smaller sizes and to distribute gas bubbles by creating turbulence. An agitator can also create partial vacuums within the process liquid and generate air bubbles via cavitation thereby pulling air into the process liquid from the headspace. If the blades of the agitator rotate too swiftly, bubbles of an undesirable large size may be generated, too much turbulence may be generated, and too much foam may be caused to form in the headspace. Thus, an appropriate amount of agitation must be utilized to accomplish specific objectives of a given process and to strike a desired balance between aeration as a result of the output of the sparger versus aeration as a result of cavitation.
Adjustments to the quantity, volume, bubble size, bubble size versus volume, and rate of gas introduced into a process liquid and to the speed of rotation of the agitator within a vessel are typically made based on past experiences, objective parameters, and yields, and not by direct observation. Further problems experienced with respect to processes in vessels relate to real time verification of mechanical operation of parts within the vessel and the cleanliness, or lack thereof, of the vessel and any internal parts.
An example of a monitoring system for a hostile environment is disclosed in U.S. Patent Application Publication No. 2002/0101508 A1 of Pollack, and an example of a probe for transmitting light through a fluid is disclosed by U.S. Pat. No. 5,182,791 issued to Pollack. Also see U.S. Patent Application Publication No. 2006/0017930 A1 of Canty et al. and U.S. Pat. Nos. 6,450,655 B1 of Walck et al., 6,782,184 B2 and 5,230,556 of Canty et al., 4,977,418 and 4,965,601 issued to Canty, 6,888,631 B2 issued to Eriksson, 5,956,077 issued to Qureshi et al. and 6,111,599 of Nance et al. for other inspection methods and apparatus.
While the monitoring and inspection systems disclosed by the above referenced patents may function in an acceptable manner, there continues to be a need for improved systems and methods enabling real time in-situ observation of processes being performed in process vessels.